Digital breast tomosynthesis (DBT) represent a new breast imaging technology recently approved by the FDA with the potential to increase cancer detection while significantly reducing the need for call back and follow up examinations. The Breast Imaging Division at the Hospital of the University of Pennsylvania will transition its screening practice that to DBT. Project 1 will take advantage of the transition DBT to measure screening related outcomes, xray dose and costs associated with routine DBT based screening and compare it to a cohort screened with planar digital mammography (DM). During the transition, patients will either undergo DBT or DM screening on a first come first serve basis. The comparison cohort will be the population screened at HUP with DM. Screening outcomes measured include call backs, follow ups, Ultrasound exams, biopsies and cancer. Mean gladular xray dose will be calculated for every projection of DM and DBT exams. Costs associated with the screening exam, and downstream costs associated with the diagnostic work up will be measured in both cohorts. Patients will be surveyed to determine the effect of DBT on satisfaction with the screening process and breast cancer worry. Given the lack of data related to the impact of DBT on breast cancer screening outcomes, project 1 will generate critical data to inform the more widespread implementation of this new technology.